Winch control



E. M. CLAYTOR `WINCH CONTROL Jan. 15, 1935.

Filed May 26, 1954 INVENTOR WITNESSES: a 7/ @Mft Edward /W C/ay for.'

` TTORNEY Patented Jan. l5, 1935 WINCH PATENT OFFICE CONTROL Edward M. Claytor, `Wilkinsburg, Pa., assigner to Westinghouse Electric & Manufacturing Company, East Pittsburgh, Pa., a corporation of Pennsylvania Application May `26, 1934, serial No. 727,747

9 Claims.

My invention relates to control systems for motors and more particularly to systems of control for motors operating Winches or similar equipment.

One object of my invention is to limit the tension of the cable in a winch or hoist to prevent breakage thereof or injury to the operating equipment.

Another object of my invention is the provision of a system of control for a winch, or other hoisting equipment adapted for mooring, towing, hoisting or other purposes which shall automatically take up slack on a moving or connecting line, and which shall automatically pay out such line when the tension therein has reached a predetermined value.

A further object of my invention is to measure the weight or the tension in a winch cable when the motor operating the winch is stopped by an overload and to restart the motor only when the tension or `weight thus measured has decreased to a selected value.

Other objects and advantages of myinvention will become more apparent from a study of the following specification and of the accompanying drawing in which the single figure is a diagrammatic showing of one embodiment of my invention comprising a winch, a driving motor therefor, a brake structure, and the electrical control for the motor.

Referring more particularly to the drawing, a winch 1 is connected to a. driving motor 2 by suitable gearing 67. An electromagnetic brake 3 is associated with the motor shaft, whichA brake 35 holds the winch drum stationary when the motor 2 is deenergized, at which time theuelectromagnet of the brake is also deenergized, A manually-operable controller 4 is provided to control the direction of operation and the speedof thelmotor 2 by means of electromagnetic contactors 5. 'y

Generally stated, the illustrated system of control limits the tension in the cable 72 by an appropriate energization and deenergization of the motor 2 and, if Vneed be, reverse energization thereof. If the motor be operating to hoist a load, the control arm 7 having been moved in the hoist direction, and the load on the motor exceeds a predetermined amount for the speed setting of the motor as determined by the setting of controller 4, an overload relay 34 will operate to deenergize the motor 2. `The magnetizing coil of the brake mechanism 3 will also be thus deenergized whereupon the brake mechanism, having a reslliently mounted casing or spring-biased base 55 and a spring-pressed brake shoe 57 mounted therein, oscillates to some extent about the axis of the brake drum, thereby moving the arm 74 and thus the link 63 upwardly to move the gear in a clockwise direction through the crank arm 64. Shaft 66 is thus rotated in a counter-clockwise direction to actuate contact arm 11 in a counter-clockwise direction a corresponding amount.

The arm 74 is provided with a shock-absorbing device 100. 'I'his device has a piston 101 in a cylinder 102.provided with a by-pass tube 103 for establishing a complete or closed circuit between the ends of the cylinder. A throttle valve 104 is disposed in the tube whereby the shock absorbing effect may be varied at will. A suitable liquid is disposed in thetube and when the arm 74 is operated the piston moves the liquid in the cylinder through the valve 104. The shock-absorbing device, as described, prevents violent actuation of arm '74 and thus provides for a smoother and more accurate control.

If the tension is very greatly increased in the cable 72 from any cause whatsoever arm 11 is moved farther in a counter-clockwise direction by an amount suilicient to reverse the connections for the motor, as hereinafter more fully set forth, in which case the motor operates in the reverse direction for a short interval of time to pay out the cable 72, thereby relieving the tension in the cable.

A better understanding of my invention can possibly be had from the study of a. typical operating cycle. Assuming that the attendant wishes to hoist a load at the maximum speed, he willthe'reupon move the plate 6 of the controller 4 by means of the control arm or handle 7 in a counter-clockwise direction whereby contact arm 11 will successively engagey plate 6 in positions a, b', and c, respectively. In position a a circuit is established from the energized conductor 13 through the conductor 14, arm 11 of the controller 4, controller segment 10, the brush l5, conductor 16, actuating coil 17 of the directional contactor 18, conductor 19, and contact members 73 of normally closed overload relay 34 to the energized conductor 20. Operation of the directional'contactor 18 closes the contact members 23, 27y and 37, thereby establishing circuits for the motor 2 and for the magnetizing coil 36 of the brake 3, respectively.

The motor circuit may be traced from the energized conductor 13 through conductor 21, eld winding 22 of the motor 2, contact member 23, conductor 24, armature 25, conductor 26, contact members 27, conductors 28 and 29, resistor sections 30 and 31 of the accelerating resistor 32 and the main coil 33 of the overload relay 34 to the energized conductor 20. The circuit for the magnetizing coil 36 of the brake 3 may be traced from the energized conductor 21 through coil 36, and contact members 37 of closed directional contactor V18 to the energized conductor 19. .Energization of the coil 36 moves the brake shoe 57 toward the left, thereby releasing the shaft of the motor 2, whereupon the motor will operate at its slowest speed, since both of the accelerating resistor sections 30 and 31 are in circuit with the motor, to hoist the load.

It should be understood that arm ,11 being mechanically coupled to the. arm 74 of the oscillating case 55 of the brake will take a position depending upon the tension in the cable 72v when the brake shoes 57 are set as shown, namely when magnetizing coil 36 is deenergized and the spring 56 moves the brake shoe 57 toward the right. However, arm 1l, by an appropriate adjustment of the relative tensions of the'biasing springs 58 and 59 onarm 74 of brake case 55, by means of the adjusting nut means 60 and 61, occupiesvthe illustrated neutral or off position for a normal or desirabletension vin the cable 72 during normal operation.

Movement of the handle 7 by a greater amount in the counter-clockwise direction, namely to the position b,'will establish a circuit for the 'rst accelerating contactor 41 from the energized conductor 14, through arm l1, controller segment 9, brush 38, conductor 39, and actuating coil 40 of the accelerating contactor 41 to the energized conductor 19.`

The movement of the handle 7 tothe full speed position c, establishes'a circuit fromk the energized conductor '14j through arm l1, controller segment 8, brush 43, conductor 44, and actuating coil 45 of the accelerating contactor 46 to the energized. conductor 19. Thedescribed operation of the accelerating contactors 41 and 46 effects the shunting of the accelerating resistor sections 31 and'30, respectively, to thus apply full voltage to the motor 2.v

In my invention, I provide a special overload relay 34 which is automatically calibrated to operate to relieve the tension inthe cable 72 when an overload having a denite relation to the speed setting of the motor occurs. Coil 33 of the overload relay34 carries the armature current of the motor whereas coil 71, additive in effect to the coil 33, is connected to the energized conductors 13 and by a circuit which may be traced from energized conductor 13 through conductor 14, flexible conductor 75, adapted to be connected to a contact member on the movable contact plate 6, either resistor section 68 orsection 69, depending on the direction of movement of the arm 7, and conductor 70 to the actuating coil 71 of the over'- load relay 34 to conductor 76 which conductor will'of course, be connected to the energized conductor 19 when either one ofthe contactors 18 or 5l have operated. It should be noted that the coil 71 is connected on the left hand side of the main contact members 73 of the overload relay 34 so that coil 7l is deenergized whenV the contact members 73 open. It should be noted that movement of the handle 7 in a counter-clockwise direction inserts more and more sectionsl of the resistor. 68 in circuit with the coil 71thereby decreasing the eiectof coil 71 for higher and higher speeds. The overload relay 34 is thus automatically calibrated so as to require larger currents in coil 33 with higher speeds before relay 34 will operate to open contact members 73. When overload relay 34 operates, the motor as well as the magnetizing coil 36 of the brake 3 is deenergized and, in consequence, the brake shoe 57 sets and the arm 11 will be moved to a position determined by the tension in the cable 72. Obviously if the controllerplate 6 is moved to engage arm 1l in position a, a smaller angular movement of arm 11 is needed to deenergize the directional contactors and the accelerating contactors at the controller 4 than would be needed if the speed of operation of the motor had been higher, namely if the controller occupied any other position than position a. To thus make the operation of the overload relay have some definite relation with reference to the angular movement that would be needed for arm 1l when there is an excessive tension on cable 72, the actuating eiect of coil 7l is made directly proportional to the angular movement of the lever or handle 7.

If the motor when operating be subjected to an excessive overload, the additive effect of coils 33 and 71 will open the contact members 73 of the overload relay 34, thereby deenergizing the directional contactor 18 andalso deenergizing the accelerating contactors 41 and 46. The actuating or magnetizing coil 36 of the brake 3 is also deenergized by reason of the opening of the contact members 37, and the oscillating case 55 oi the brake 3, since the brake shoes 57 immediately set, moves in a clockwise direction about the shaft of the armature to increase the tension in the lower balancing spring 59 and move the link 63 upwardly to thus rotate the gear 65, by the clockwise movement of the crank 64, in a clockwise direction thereby moving the shaft66 connected to the arm 11Y in a counter-clockwise direction by an amount suicient to move the arm 11 to the neutral position, or position shown` in the Figure. This proper angular movement must necessarily follow by reason of the self-calibrating overload relay 34.

From the foregoing explanation it is apparent that an overload on the motor stops the winch and then the tension or weight on the cable is measured. The movement of arm 11 is an in'- dication of the weight being hoisted. When the n weight thus measured is decreased to a certain value, the motor may restart to continue the hoisting of the load. On the other hand if the weight increases above a certain value the motor restarts to pay out cable, as subsequently delscribed. I Accelerating contactors 4l and 46, as well as the directional contactor 18, have an additional gap in the circuits of their respective operating coils, namely, at the controller 4, by reason of the movement of arm 11 back to neutral position, for example, and since the overload relay also hasits circuit for both coils 33 and 7l openedby reason of the opening of the contact members 27 and 73, respectively, contact members 73 again close.

Closing of the contact members 73 will however, have no effect on the directional contactors nor the accelerating contactors so long'as there is an excessive tension in the cable 72, because as'long as the tension persists, arm l1 will remain in the neutral or off position. After the tension has been relieved, which will normally occurautomatically, and within a short interval of time, since the motor no longer operates' the hoisting drum, the arm 11 movesback by reason of the actuation of the springs` 58 andA 59 to the particular speed setting made by the at- Cal Lesmo? `tendant when nrst accelerating the motor by moving the handle 7. When this occurs, the motor 2 is Vagain automatically energized and the hoisting operation is resumed.

If for any reason, `the tension in the cable 72 be very great, so that the movement of the arm 11 when the brake shoe 57 sets is out of `proportion with respect to the overload that occurred on the overload relay 34, the arm moving to position a', for example, a reverse circuit is established for the motor 2 which circuit may 'be traced from the energized conductor 14 through arm 11, controller segment 12, brush 48, conductor 49, actuating coil 50 of the reverse directional contactor 51 to the energized conductor19.' Closing of the directional contactor 51 establishes an energizing circuit for the magnetizing coil 36 of the brake 3 through the contact members .52 and also establishes a reverse circuit; for the motor amature 25 throimh the '55 is, of course, released bythe energization of the coil"36 and arm 11 would be immediately moved to the neutral position, thus preventing any substantial paying out of the cable 72. Normally,A no great amount of cable needs to be paid out when there is a rise in tension in the cable 72, but to prevent the arm 11 from immediately opening the reverse circuit for the motor, the directional contactor 51 is provided with a very low resistance short-circuited coil 80 to give it a considerable time constant. This time constant or delayed operation of the directional contactor 51 holds the contact members 52, 53 and 54 closed for an interval of time suicient to pay out the necessary amount of cable 72 to relieve the tension.

If continuous reverse operation is desired, it is of course obvious that lever 7 may be moved in the lowering or clockwise direction whereupon arm 11 will take positions a', b or c' as desired, and again the coil 71 will be automatically calibrated to have an operating effect proportional to the angular movement of the lever 7. For the lowering direction, this is usually not so important, since an overload is not likely to occur, for in many instances the load may even be overhauling and the control is thus not symmetrical although it is shown substantially symmetrical and would be symmetrical except for the fact that directional contactor 51 is provided with a timing circuit.

With the devices heretofore supplied to the market, the motor had to be a motor having a continuous rating, that is, one that had to be comparatively large to successfully operate continuously with a full load on the winch 1 in actual operation. Since the demand on a hoist or winch motor is always intermittent, a rest period being interposed between successive operations, it would constitute a valuable advance in the art to provide control means for a winch and the driving motor therefor which would permit the use of an intermittently rated motor.

An intermittently rated motor can be much smaller and the equipment thus much cheaper if such motor can be used, My control permits the use of such smaller motor and so controls the equipment that the smaller motor is nevertheless not overheated and the' insulation will not be injured by reason of the rest periods allowlng for proper cooling of the motor after each operation. With my system of control, this object ls attained, as it is obvious that the motor can be an intermittently rated motor and the cost of the equipment is thus very much reduced and its efficiency is improved. This is particularly important where the winch is to be installed on board ship where the question of weight is always an important one.

I am fully aware that inv invention is susceptible of other modifications and applications not herein specically disclosed, particularly by those skilled in the art after having had the benefit o! the teachings of my invention. It is, therefore, to be understood that my invention ls not to be limited to the specific circuit arrangements shown nor the application made but is only to be limited by the scope of the claims hereto appended and the pertinent prior art.

I claim as my invention:

1. In a system of control for a winch, in combination, a winch having a drum and a hauling cable wound thereon, a motor for driving the winch, anV electromagnetic brake having a movable drum connected to the motor shaft and a brake shoe adapted Ato hold the motor shaft and thus the winch in position, said brake shoe being mounted on a spring-biased base adapted to oscillate about the -center of the brake drum, a controller arm adapted to be moved by the springbiased base when said brake shoe engages the brake drum proportionally to the tension in the cable, an overload relay adapted to deenergize the motor and set the brake shoe when a predetermined overload is on the motor, and means, operable only when the motor is deenergized, for energizing the motor for haul in rotation when the arm is moved by a decrease in the tension in the cable.

2. In a system of control for a motor operating a hoist, in combination, a hoist and a cable, a motor driving the hoist, a source of energy for the motor, overload means, adapted to be energized inversely proportional to the voltage impressed on the motor armature and proportional to the motor load, for disconnecting the motor from the source of energy, and means, responsive, after the motor is deenergized, to the tension in the cable, adapted to reenergize the motor.

3. In a system of control for a motor operating a hoist, in combination, a winch operating a cable, a motor driving the winch, a source of energy for the motor, a controller, a lever of the controller adapted to be actuated in response to the tension in the cable after the motor is deenergized, controller means adapted to be moved relative to the lever to provide a certain speed setting for the motor, overload means, responsive to the load on the motor and the voltage impressed on the motor armature, adapted to disconnect the motor from the source of energy, and means adapted to move said lever to counteract the movement of said controller means as a function of the tension in the cable after the motor is deenergized to thus prevent reenergization of the motor as long as the tension in the cable is above a certain value, and means reenergizing the motor by a movement of the lever when the tension deereasesfbelow a vCertain Value. l

'tively by a current proportionalto the vmotor current and by a current inverselyproportional vto the voltage selected to be impressed on `the motor armature, to deenergize said motor, and means responsive to the tension inthe cable4 of Athe Winch to reenergize the motor; y l

' 6. In a control fora Winch,..in combination, a motor for driving the winch,v a,bi"al:e` a, controller for the motor comprising ,an armzadapted to be moved as a function of ,the'tension in the Winch cable after the motor is deenergized and the brake set and a member movable With'reference to the nation, a 'source of energy, a motor adapted to be Ienergized from said source, overload means, responsive jointly tothe motor current and inversemovable arm to thus control the speedof .the motor, overload means responsivejointly to' overload and the position of the movable member .to deenergize the motor and set the brake, and means adapted to reenergize said motor lfor'hoist'rotation, after a specifledfoverload, when theicable ,tension has decreased toa predeterminedvaluezf '7.vIn a system of control, in combinationfa motor, a source of energy, acontroller-oomprising predetermined normal load on the motor, a controller element adapted to be movable with refspect tof thel armto energize said motor, means for nullifying theeffect of the movement of the controller elementwithreference to the arm and means responsive to the torque on the motor shaft to reenergize said motor, said means being responsive to the torque on thel motor shaftV only after the motor is deenergized.

8.- In-a system of control for a motorpoperating shaft.y after the motor has lbeen deenergized, as

- determined by thevtension inthe cable, and means for v energizing the motor either fto haul in the .calc le-o rE pay- 'it out, in response to the angular ,Ashiftin the,-mo unting by. reasons of Variations in the tension of the cable, said means being responsive to the cablev tension only after the motor .is vdeenergized.A

9. In a system of control lfor a motor, in combilylto the voltage impressed on said motor, adapted ,to disconnect said motor from said source of fenergy," andmeans responsive,after the actuation of-esaid overload'means,l toreenergize said motor as agfunction `of the torque on the motor shaft.

` EDWARD M. CLAYTOR. 

